Lake Michigan is one of the five Great Lakes of North America. It is the second-largest of the Great Lakes by volume and the third-largest by surface area, after Lake Superior and Lake Huron. To the east, its basin is conjoined with that of Lake Huron through the 3+1⁄2-mile wide, 295-foot deep Straits of Mackinac, giving it the same surface elevation as its easterly counterpart; the two are geologically a single lake.